Manufacture of hardened or tempered glass plates



`May 11, 1937. R, MAGNlEN 2,080,083

MANUFACTURE OF HARDENED OR TEMPERED GLASS PLATES Filed May 22, 1955 2 Sheets-Sheet l May 1l, 1937. R MAGMEN 2,080,083

v MANUACTURE QF HARDENED 0R TEMPERED GLASS PLATES Filed May 22, 1935 2 Sheets-Sheet 2 IKA(/// INVENTOR Hay 7770771 /Wzjwu'vz TTORNE Y Patented May 411 1937 yUNITED STATESA PATENT OFFICE MANUFACTURE OF HARDENED R TEMPERED GLASS PLATES Raymond Magnien,l

Socit Assurex LeRoi Paris, France, assignor to des Verres de Scurit.

Magnien, Monnier & Cie., a corporation of France, and Lon Alfred Edouard Petit Application May 22, 1.935, Serial No. 22,904 In France June 8, 1934 3 Claims.

point and then suddenly cooled.

In order to obtain a sudden cooling eiect it has been proposed to use cold air jets which are uniformly distributed on both sides of the 1n plate. The local cooling produced by the said air jets produces a system of tensions and compressions forming an equilibrated net having particular resistance properties and, in the case of breakage, .the property of breaking into pieces of small dimensions. n

The use of a system of cold air jets regularly distributed opposite the plate to be hardened causes a maximum cooling at certain predetermined points which are surrounded by concentric zones where the cooling takes place more slowly. Such a process produces a hardened glass having the desired properties, but it has been found that local deformations and visible irisations were produced, which were prejudicial to the neat appearance andthe transparency of the hardened glass plates. v

In order to remedy such disadvantages, it has been proposed to provide a rotary movement, generally a circular movement, between the glass plate and the air jets.

In fact this method permits of better distribution of the hardening effects according to predetermined lines, to regulate the rate of cooling and thus to diminish the irisations, but -this solution requires the use of mechanical devices which are expensive and delicate in operation.

Furthermore, with the movable air jets as Well as with the fixed air jets, the air being heated through 'its contact with the glass plate 40 tends to rise along the latter. The result of this is that a stream of hot air is produced along the plate, which counteracts the effect of the normal `air jets, particularly in the upper part of the plate. The hardening effect is irregular over the whole surface and if the plate is one' of large dimensions it may even happen that a part of the same is ill-hardened or not hardened at all.

This invention provides a methodand a device for hardening glass plates, which permit of insuringa convenient cooling in predetermined directions and a uniformhardening on the whole surface of the glassl plate for any dimension of the latter without the use of mechanical devices.

temperature which is higher than its softeningv (Cl. ill-45) This method comprises providing in contact with the glass plate xed regular air streams of positive directions through simultaneous blowing'and suction. The air is blown through openings of small dimensions arranged along the 5 sides of a network of adjacent regular polygons and it is sucked after having passed over the plate through larger openings arranged in the middle of the4 said regular polygons.

'I'his method insures a definite path for the 10 air jets and thus there is no hot air current along the plate counteracting the passage of the upper air jets, as with the known methods. As

-the air jets are fixed and distributed in predetermined directions, the cooling is regularly 15 effected from the sides of the blowing'polygons to the middle of the latter, thus providing a `predetermined network of tensions and compressions.

'I'he blowing and the suction may be regulated 0 -the air projected on to the material which has 25 been brought to its softening point.

In a device for carrying this method into effect, the suction and blowing openings are distributed on a plane surface which is brought to the neighbourhood of the glass plate to be treated. 3'0

The distance between the said plane surface and the glass plate can be adjusted as desired. The plane surface provided with the openings is integral with two boxes, one of the said boxes receiving the ai'r under pressure and being in 35 communication with the small blowing openings, while the other is lsubject t'o a vacuum and receives the air which is drawn in through the large suction openings. Such a device may be provided for acting either on one side or on 40 both sides of the glass plate. In this latter case, the openings which are on both sidesI of the plate are advantageously alternated in order better to distribute the effects of cooling.

A construction of the device according to the 45 invention is shown by way of example in the' accompanying drawings, in which Figure 1 is a diagrammatic View of the arrangement of the blowing and suction openings.

Fig. 2 is afragmentary view in section of a 50 plate of glass with an air-circulating device on each side thereof. g

The openings which are shown in full lines relate to the device-located on the one side of the glass plate and the openings indicated in 55 dotted unes relate to the device located on tn other side.

The device for hardening glass plates comprises -a series of blowing openings i of small dimensions 5 arranged along the sides of adjacent regular polygons.

The saidl polygons arey preferably regular hexagons as shown in the drawings. f They may also be regular polygons having a largerforsmaller l0 number ofY sides.

In the middle of the said hexagons larger openings 2 are arranged which serve for the suction v jets. The whole of the openings 2 is thus arranged in staggered relation on successive lines.

l5 On the opposed surface of the glass plate there is provided asimilar device formed of blowing openings l" and of suction openings 2' andthe said openings are advantageously arranged in staggered relation with respect to the openings I 20. and 2, the displacement being by a linear distance equal to the length of a side of the polygon. In a convenient arrangement of the openings (Figure 2) the openings l-I' and 2-2 are arranged on two plane plates 3 and 3'. The open- 25 ings I are in communication with a box! in which `the air is maintained under pressure either by a fan or .through a connection with a source of compressed air which is provided. if necessary, with a pressure reducing valve. The openings 2 are 30 connected through branches 5 which pass through 40 for preheating .of any'kind, for instance for preheating the glass plate, which permits recovering the sensible heat of the preheated air.

Adjusting devices s uch as throttle valves or slide valves (not shown) may be. provided for ad- `45 justine the equality or che blowing on each side of 2, .oas

the plate 1. They may also provide for adjusting the suction and the blowing with respect to each other. In alike manner, devices (not shown) may be provided for adjusting the distance between the surfaces 3 and 3' and the plate I to be hardened, according to the thickness ofthe plate and its dimensions. f Having now particularly described and ascertained the nature of my lsaid inventionl and in what manner the same is to be performed, I declare that what I claim is:-

1. Apparatus for the non-isotropic hardening of glass plates, comprising a casing having one f of its walls parallel to and spaced from one surface of the glass plate to behardened, a pressure chamber and a suction chamber in said casing, a series of nozzles extending from the pressure chamber to the outer surface of the wall and arranged along the sides of contiguous regular polygons, and a second series o f nozzles extending from the suction chamber to said sur- `face, these suction nozzles being of larger crossof the glass plateto be hardened, a pressure chamber anda suction chamber in said casing, a series of nozzles extending from the pressure chamber to the outer surface of the wall and arranged along the sides of contiguous regular hexagons, and a second series of nozzles extending from the suction chamber to said surface, these-suction nozzles being of larger cross-section than the of one of the said hexagons.

RAYMOND MAGNIEN. 

